Radius of Gyration: R^2 = √(Lζ/3)

In summary, the conversation discusses the calculation of <Rg^2>, the radius of gyration, which is defined as 1/N times the sum of (Ri-Rc)^2, where Rc is the center of mass and is equal to 1/N times the sum of Ri. The problem at hand is to prove that sqrt(<Rg^2>) is equal to sqrt(Lζ/3), with L being a constant and ζ being a variable. The conversation also mentions a step in the proof that is uncertain, which involves showing that 1/N times the sum of (Ri-1/N times the sum of Ri)^2 is equal to 1/(2N^2) times the sum
  • #1
jaobyccdee
33
0
With <Rg^2>=1/N [sum[(Ri-Rc)^{2}>] where Rc is the center of mass, =1/N sum Ri, and provided that <R^2>=2Lζ .Show that sqrt(R^{2})=sqrt(L ζ /3)
 
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  • #2
It would perhaps help if you defined all the variables, and what the problem is actually asking...
 
  • #3
<Rg^2> is the radius of gyration. Ri-Rc is the distance between the monomers and the center of the polymer. The problem is that give <Rg^2>=1/N Sum<( Ri-Rc )^2>, and that Rc=1/N sum Ri. proof that sqrt(<Rg^2>) = sqrt(Lζ/3). Actually i was working on it, and there is a step that i m not sure, and it's that if 1/N Sum<(Ri-1/N Sum(Ri)>^2 ==1/(2N^2) <sum of [i,j] (Ri-Rj)>^2
 
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1. What is the formula for calculating the radius of gyration?

The formula for calculating the radius of gyration is R^2 = √(Lζ/3), where R is the radius of gyration, L is the length of the object, and ζ is the moment of inertia.

2. What does the radius of gyration represent?

The radius of gyration represents the distance from the axis of rotation at which the entire mass of an object can be concentrated to produce the same moment of inertia as the object itself.

3. How is the radius of gyration related to an object's mass distribution?

The radius of gyration is inversely proportional to an object's mass distribution. This means that the larger the radius of gyration, the more spread out the mass is, and the smaller the radius of gyration, the more concentrated the mass is.

4. Can the radius of gyration be used to calculate an object's rotational kinetic energy?

Yes, the radius of gyration can be used to calculate an object's rotational kinetic energy. The equation is T = 1/2Iω^2, where T is the rotational kinetic energy, I is the moment of inertia, and ω is the angular velocity.

5. How is the radius of gyration used in real-world applications?

The radius of gyration is used in various real-world applications, such as in the design and analysis of rotating objects like propellers, flywheels, and gymnastics equipment. It is also used in structural engineering to determine the stability and strength of buildings and bridges.

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